On Mon, 25 Aug 2025 09:18:53 +0800 Coiby Xu <c...@redhat.com> wrote:
> >diff --git a/arch/arm64/kernel/kexec_image.c
> >b/arch/arm64/kernel/kexec_image.c
> >index 532d72ea42ee8..287b25e674d76 100644
> >--- a/arch/arm64/kernel/kexec_image.c
> >+++ b/arch/arm64/kernel/kexec_image.c
> >@@ -76,6 +76,7 @@ static void *image_load(struct kimage *image,
> > kbuf.buf_min = 0;
> > kbuf.buf_max = ULONG_MAX;
> > kbuf.top_down = false;
> >+ kbuf.random = 0;
> >
> > kbuf.buffer = kernel;
> > kbuf.bufsz = kernel_len;
> >
>
> And also thanks for posing a fix! The patch LGTM. Can you add a Fixes
> tag 'Fixes: bf454ec31add ("kexec_file: allow to place kexec_buf
> randomly")' and then send it to kexec@lists.infradead.org? Thanks!
I turned all this into a regular patch and queued it (see below),
thanks. No additional actions are needed.
I'm really not liking that code. I laboriously verified that all
fields of kexec_buf are now initialized, except for `cma'. Is that a
bug?
This function has a call frequency of about 3x per week. Can we please
just memset the whole thing so people don't have to worry about this
any more?
From: Breno Leitao <lei...@debian.org>
Subject: kexec/arm64: initialize the random field of kbuf to zero in the image
loader
Date: Thu Aug 21 04:11:21 2025 -0700
Add an explicit initialization for the random member of the kbuf structure
within the image_load function in arch/arm64/kernel/kexec_image.c.
Setting kbuf.random to zero ensures a deterministic and clean starting
state for the buffer used during kernel image loading, avoiding this UBSAN
issue later, when kbuf.random is read.
[ 32.362488] UBSAN: invalid-load in ./include/linux/kexec.h:210:10
[ 32.362649] load of value 252 is not a valid value for type '_Bool'
Link:
https://lkml.kernel.org/r/oninomspajhxp4omtdapxnckxydbk2nzmrix7rggmpukpnzadw@c67o7njgdgm3
Fixes: bf454ec31add ("kexec_file: allow to place kexec_buf randomly
Signed-off-by: Breno Leitao <lei...@debian.org>
Cc: Baoquan He <b...@redhat.com>
Cc: Coiby Xu <c...@redhat.com>
Cc: "Daniel P. Berrange" <berra...@redhat.com>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: Dave Young <dyo...@redhat.com>
Cc: Kairui Song <ryn...@gmail.com>
Cc: Liu Pingfan <kernelf...@gmail.com>
Cc: Milan Broz <gmazyl...@gmail.com>
Cc: Ondrej Kozina <okoz...@redhat.com>
Cc: Vitaly Kuznetsov <vkuzn...@redhat.com>
Cc: <sta...@vger.kernel.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
---
arch/arm64/kernel/kexec_image.c | 1 +
1 file changed, 1 insertion(+)
---
a/arch/arm64/kernel/kexec_image.c~kexec-arm64-initialize-the-random-field-of-kbuf-to-zero-in-the-image-loader
+++ a/arch/arm64/kernel/kexec_image.c
@@ -76,6 +76,7 @@ static void *image_load(struct kimage *i
kbuf.buf_min = 0;
kbuf.buf_max = ULONG_MAX;
kbuf.top_down = false;
+ kbuf.random = 0;
kbuf.buffer = kernel;
kbuf.bufsz = kernel_len;
_
